Device for detecting internal pressure of air-filled gunwale protector

ABSTRACT

The present invention relates to an internal-pressure detection apparatus for a pneumatic fender that can reduce the labor of maintenance. The internal-pressure detection apparatus is configured of an internal-pressure detection unit  10  provided in a pneumatic fender that is fixed to an underwater structure such as a quay  2  and bridge pier  3  or floated and is used as cushioning material for a ship or the like, and a monitor unit  20  provided in an internal-pressure monitoring station  4  on land. The internal-pressure detection unit  10  is driven by the energy of an electromagnetic wave having a first frequency, and detects internal air pressure of the pneumatic fender  1 ; transmits this air pressure information by an electromagnetic wave having a second frequency. The monitor unit  20  not only transmits the electromagnetic wave, having the first frequency, at the time of internal air pressure detection, but also receives the electromagnetic wave having the second frequency, and obtains the air pressure information transmitted from the internal-pressure detection unit  10 ; informs a monitoring person of this air pressure information with displaying the air pressure information on a display unit or the like. Thereby, it is possible to easily install the internal-pressure detection apparatus and to reduce the labor of maintenance for battery change or the like.

TECHNICAL FIELD

The present invention relates to an internal-pressure detect ionapparatus for a pneumatic fender.

BACKGROUND ART

Conventionally, in order to prevent a ship from contacting to or beingdamaged due to collision within underwater structure such as a bridgepier and a quay, contact of the ship to the underwater structure isprevented by fixing pneumatic fenders to the underwater structure orfloating pneumatic fenders on the water.

Such a pneumatic fender is made as cushioning material fill ed with airinside the pneumatic fender, and hence, if its air pressure decreasesdue to leakage of internal air, its function is impaired. For thisreason, the internal air pressure is kept at a designated value bymeasuring the air pressure inside the fender through periodical patroland supplementing the fender, whose internal air pressure is decreased,with air.

Nevertheless, since it requires much labor to check the air pressureinside the fender by manual patrol, systems monitoring the air pressureof the fender by using cables (Japanese Utility Model Application No.61-112243) or a radio wave (Japanese Patent Application Laid-Open No.60-46438) are also used.

Nevertheless, in a system monitoring air pressure of each fender usingcables as disclosed in the Japanese Utility Model Application No.61-112243, it was necessary to connect each fender to a monitoringstation with a hose, and hence it needed not only much labor to installthe system, but also much time to maintain the system itself.

In addition, in a system monitoring air pressure inside a fender using aradio wave as disclosed in Japanese Patent Application No. 60-46438, abattery has been used in a transmitter (radio wave transmitter) providedin the fender. Therefore, in order to prevent the transmitter fromstopping operation, it was necessary to periodically replace thisbattery. Hence, although installation of the system has beencomparatively easy, this system has been a problem that it requires muchlabor to maintain the system.

An object of the present invention is, in consideration of aboveproblems, to provide an internal-pressure detection apparatus for apneumatic fender that can reduce the labor of installation andmaintenance.

DISCLOSURE OF THE INVENTION

In order to attain the object described above, the present inventionprovides not only an internal-pressure detection unit in a pneumaticfender that is fixed to an underwater structure or floated and is usedas cushioning material for a ship or the like, but also a monitor unitin an internal-pressure monitoring station Furthermore, the presentinvention transfers an air pressure value inside the pneumatic fender,which is detected by the internal-pressure detection unit, to themonitor unit by an electromagnetic wave, and thereby makes it possibleto monitor internal air pressure of all the pneumatic fenders, which areobjects to be monitored, in the internal-pressure monitoring station.

The internal-pressure detection unit described above converts the energyof an electromagnetic wave having a first frequency, which is receivedby means of reception, into electric energy, and thereby operates bythis converted electric energy. Furthermore, the internal-pressuredetection unit detects the air pressure inside a pneumatic fender by apneumatic sensor, and transmits this detection result by anelectromagnetic wave having a second frequency.

On the other hand, the monitor unit described above not only suppliesoperation energy to the internal-pressure detection unit by transmittingthe electromagnetic wave, having the first frequency by means oftransmission, but also informs of a detection result of the air pressureby receiving the electromagnetic wave having the second frequency thatis transmitted from the internal-pressure detection unit.

For example, the internal-pressure detection unit described abovecomprises a pneumatic sensor that detects air pressure inside apneumatic fender and outputs an electric signal corresponding to the airpressure value, means of reception for receiving an electromagnetic wavehaving a first frequency, means of energy conversion for converting theenergy of the electromagnetic wave, received by the means of reception,into electric energy, and means of transmission for operating by thisconverted electric energy, inputting an electric signal outputted fromthe pneumatic sensor, and transmitting a detection result of the airpressure by an electromagnetic wave having a second frequency.

In addition, the monitor unit described above comprises means oftransmission for transmitting the electromagnetic wave having the; firstfrequency, means of reception for receiving the electromagnetic wavehaving the second frequency and converting the electromagnetic wave intoan electric signal, means of detection result extraction for extractingthe detection result of the air pressure, which is included in theelectric signal outputted from the means of reception, and means ofinformation for informing of the detection result extracted

According to the internal-pressure detection apparatus for a pneumaticfender that has the configuration described above, in theinternal-pressure detection unit, the electromagnetic wave having thefirst frequency that is transmitted from the monitor unit is received bythe means of reception. Furthermore, the energy of this electromagneticwave is converted into electric energy by the means of energyconversion, and is supplied to the pneumatic sensor and the means oftransmission.

Thereby, the internal-pressure detection unit operates by the energy ofthe electromagnetic wave having the first frequency received and henceit is unnecessary to provide any power supply such as a storage cell.Hence, it is unnecessary to periodically replace the storage cell, andhence it is possible to omit the labor of maintenance.

Furthermore, the air pressure of the pneumatic fender is detected by thepneumatic sensor in the internal-pressure detection unit, and anelectric signal corresponding to the air pressure value detected isoutputted from the pneumatic sensor. This electric signal is inputted tothe means of transmission, and the detection result of the air pressureis transmitted by the electromagnetic wave having the second frequency.

On the other hand, in the monitor unit, the electromagnetic wave havingthe first frequency is transmitted by the means of transmission at thetime of detecting the air pressure, and the electromagnetic wave havingthe second frequency that is transmitted from the internal-pressuredetection unit is received by the means of reception and is convertedinto an electric signal.

The detection result of the air pressure that is included in theelectric signal outputted from the means of reception is extracted bythe means of detection result extraction, and then this detection resultextracted is informed by the means of information.

Therefore, it is unnecessary to install cables between the pneumaticfender and monitoring station, and hence it is possible to omit thelabor of installing cables like the conventional example.

In addition, by not only providing, in the internal-pressure detectionunit, means of identification-information memory for storing theidentification-information inherent in each internal-pressure detectionunit, and means of transmission for transmitting thisidentification-information and the detection result of the air pressureby the electromagnetic wave having the second frequency, but alsoproviding, in the monitor unit, means of detection result extraction forextracting the detection result of the air pressure andidentification-information from the electric signal outputted from themeans of reception, and means of information for informing of theextracted identification-information and detection result in aone-to-one correspondence between them, it becomes possible to identifythe detection result transmitted from the internal-pressure detectionunit mounted to each pneumatic fender if there are a plurality ofpneumatic fenders that are objects to be managed.

That is, the identification-information inherent in eachinternal-pressure detection unit is stored in the means ofidentification-information memory, and the detection result of the airpressure and the identification-information are transmitted by the meansof transmission in the internal-pressure detection unit by theelectromagnetic wave having the second frequency.

Furthermore, in the monitor unit, the detection result of the airpressure and the identification-information are extracted by the meansof detection result extraction, and then the means of informationinforms a monitoring person of this extracted identification-informationand detection result in a one-to-one correspondence between them.

Thereby, when each detection result of the plurality ofinternal-pressure detection units is monitored at one monitor unit, theinternal-pressure detection result of each pneumatic fender can beidentified on the basis of the identification-information.

In addition, by providing, in the internal-pressure detection unit,means of identification-information extraction for extractingidentification-information included in a high-frequency signal receivedby the means of reception, means of identification-information matchingdecision for deciding matching this identification-information extractedto own identification-information stored in the means ofidentification-information memory, and the means of transmission drivecontrol for driving the means of transmission when matching according tothis decision result, and providing, in the monitor unit, the means ofmemory for storing the identification-information of internal-pressuredetection units provided in the pneumatic fenders that are objects to bedetected, and means of transmission for transmitting this storedidentification-information, which is stored, by the electromagnetic wavehaving first frequency, it becomes possible to obtain the detectionresult of the air pressure by designating one from among the pluralityof pneumatic fenders that are objects to be managed.

That is, at the time of detecting the air pressure, in the monitor unit,the identification-information, which is stored in the means of memory,of the internal-pressure detection unit provided in the pneumatic fenderthat is an object to be detected is transmitted by the means oftransmission by the electromagnetic wave having the first frequency.

Furthermore, in the internal-pressure detection unit, theidentification-information included in the high-frequency signalreceived by the means of reception is extracted by the means ofidentification-information extraction. Matching thisidentification-information extracted to the ownidentification-information stored in the means ofidentification-information memory is decided by means of theidentification-information matching decision. Then, when matchingaccording to this decision result, the means of transmission is drivenby the means of transmission drive control, and the ownidentification-information and detection result of the air pressure aretransmitted.

Thereby, if there are a plurality of pneumatic fenders that are objectsto be managed or there are a plurality of internal-pressure detectionunits, it becomes possible to transmit the detection result bydesignating an arbitrary internal-pressure detection unit.

In addition, by not only providing, in the internal-pressure detectionunit, means of instruction extraction for extracting an information-readinstruction and an information-write instruction which are included inthe high-frequency signal received by the means of reception, means ofidentification-information matching decision for deciding matching theidentification-information extracted by the means ofidentification-information extraction to the identification-informationstored in the means of identification-information memory, means ofinformation memory, the means of information write for writinginformation, which is an object to be written and follows aninformation-write instruction, into the means of information memory whenmatching according to the decision result of means of theidentification-information matching decision and receiving theinformation-write instruction, the means of information read for readinginformation, which is stored in the means of information memory, whenmatching according to the decision result of means of theidentification-information matching decision and receiving theinformation-read instruction, and means of transmission for transmittingthis information which is read by the electromagnetic wave having thesecond frequency, but also providing, in the monitor unit, the means ofinstruction input for inputting an information-write instruction andinformation, which is an object to be written, to the means ofinformation memory in the internal-pressure detection unit, and aninformation-read instruction from the means of information memory, themeans of information extraction for extracting the information that isstored in the internal-pressure detection unit and is included in theelectric signal outputted from the means of reception, means oftransmission for transmitting the instructions and information, whichare inputted by the means of instruction input, by the electromagneticwave having the first frequency, and mean's of information for informinga monitoring person of the information extracted by the means ofinformation extraction, it becomes possible to allow a pneumatic fenderitself to store and hold information such as maintenance records byrecording the information, being inherent in each pneumatic fender, inthe means of information memory of the internal-pressure detection unit,and to access this information according to necessity.

That is, if the information-write instruction or information-readinstruction is inputted by the means of instruction input in the monitorunit, these instructions are transmitted by the means of transmission bythe electromagnetic wave having the first frequency.

The instructions transmitted from the monitor unit by theelectromagnetic wave having the first frequency are received by themeans of reception in the internal-pressure detection unit. Theseinformation-read instruction and information-write instruction, whichare included in the high-frequency signal received, are extracted by themeans of instruction extraction in the internal-pressure detection unit.

Furthermore, in the internal-pressure detection unit, matching theidentification-information, which is extracted by the means ofidentification-information extraction, to the ownidentification-information stored in the means ofidentification-information memory is decided by means of theidentification-information matching decision. When matching according tothe decision result and receiving the information-write instruction,information that is an object to be written and follows thisinformation-write instruction is written into the means of informationmemory by the means of information write.

In addition, when matching according to the decision result, of means ofthe identification-information matching decision and receiving theinformation-read instruction, information that is stored in the means ofinformation memory is read by the means of information read at theinternal-pressure detection unit. This information read is transmittedby the means of transmission by the electromagnetic wave having thesecond frequency.

Furthermore, the information transmitted from the internal-pressuredetection unit is received by the monitor unit, and is informed by themeans of information.

Thereby, it becomes possible to access information in the means ofinformation memory of the internal-pressure detection unit as the needarises.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing for explaining the configuration of aninternal-pressure detection apparatus for a pneumatic fender in anembodiment of the present invention.

FIG. 2 is an outside drawing showing the pneumatic fender in anembodiment of the present invention.

FIG. 3 is a block diagram showing an electric circuit of aninternal-pressure detection unit in a first embodiment of the presentinvention.

FIG. 4 is a block diagram showing an electric circuit of a monitor unitin the first embodiment of the present invention.

FIG. 5 is a block diagram showing an electric circuit of aninternal-pressure detection unit in a second embodiment of the presentinvention.

FIG. 6 is a block diagram showing an electric circuit of a monitor unitin a third embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be describedwith reference to drawings.

FIG. 1 is a drawing for explaining the configuration of aninternal-pressure detection apparatus for a pneumatic fender in a firstembodiment of the present invention. In the drawing, reference numeral 1is a pneumatic fender (hereinafter, this is simply called a fender),which is used as cushioning material for a ship or the like with beingfixed to an underwater structure such as a quay 2 and bridge pier 3 orbeing floated on the water. Reference numeral 4 is an internal-pressuremonitoring station (hereinafter, this is simply called a monitoringstation) provided on land, which monitors air pressure inside eachfender 1.

The pneumatic fender 1, as shown in FIG. 2, has a barrel-like shapeobtained by sealing both ends of a rubber tube that is approx. 1-2 m indiameter and approx. 3-4 m long, and has a filler hole 1 a of air in anend; the inside is filled with air of the predetermined internalpressure through this filler hole 1 a. Furthermore, an internal-pressuredetection unit 10, which detects air pressure inside the fender andtransmits this information by an electromagnetic wave, is provided inthe proximity to the filler hole 1 a.

Internal-pressure information (air pressure information inside thefender 1) transmitted from the internal-pressure detection unit 10 isreceived by the monitor unit 20 provided in the internal-pressuremonitoring station 4, the internal air pressure of each fender 1 ismonitored by a monitoring person, and air supplement to and maintenanceof the fender 1 is performed on the basis of this.

FIG. 3 is a block diagram showing an electric circuit of theinternal-pressure detection unit 10. In the drawing, 10 is theinternal-pressure detection unit, which is configured of a transmissionand reception antenna 11, a rectifier circuit 1, a central processingunit 13, a pneumatic sensor 14, a transmission unit 15, and a duplexer16.

The rectifier circuit 12 is configured of diodes 121 and 122, acapacitor 123, and a resister 124, and forms a known full-wave rectifiercircuit. The transmission and reception antenna 11 is connected to theinput side of this rectifier circuit 12 through the duplexer 16, andthis rectifier circuit 12 outputs rectified current as a driving powersupply of the central processing unit 13, pneumatic sensor unit 14, andtransmission unit 15 by rectifying high-frequency current, which isinduced in the transmission and reception antenna 11 and passes throughthe duplexer 16, and converting the induced current into direct current.

The central processing unit 13 is configured of a known CPU 131, and adigital/analog (hereinafter, this is called D/A) converter 132 thatoperate with a preset program.

When electric power is supplied from the rectifier circuit 12 to the CPU131 and the CPU 131 becomes operable, the CPU 131 converts an analogsignal, which is outputted from the pneumatic sensor 14, into digitaldata and outputs the information of air pressure inside; the fender 1,which is based on this data, to the transmission unit 15 through the D/Aconverter 132.

The pneumatic sensor 14 is configured of, for example, a capacitancetype pressure sensor, a semiconductor pressure sensor, a piezoelectricpressure sensor, or the like, and outputs an analog electric signalcorresponding to the air pressure inside the fender The transmissionunit 15 is configured of an oscillator 151, a modulator 152, and ahigh-frequency amplifier 153.

The oscillator 151 generates a carrier wave having a frequency of, forexample, 300 MHz. The carrier wave outputted from the oscillator 151 ismodulated by the modulator 152 on the basis of an information signalinputted from the central processing unit 13 and is outputted.Furthermore, this carrier wave modulated is supplied to the transmissionand reception antenna 11 through the high-frequency amplifier 153 andduplexer 16. Thereby, an electromagnetic wave having a frequency of 300MHz is radiated from the transmission and reception antenna 11.

The duplexer 16 is configured of a low-pass filter 16 a and a high-passfilter 16 b, the low-pass filter 16 a is connected between thetransmission and reception antenna 11 and rectifier circuit 12; and thehigh-pass filter 16 b is connected between the transmission, andreception antenna 11 and high-frequency amplifier 153.

Here, the duplexer 16 achieves separation between a High-frequencysignal, having a first frequency (100-300 KHz), and a high-frequencysignal having a second frequency (300 MHz). For example, the low-passfilter 16 a is a filter passing a high-frequency signal at 1 MHz orlower, and the high-pass filter 16 b is a filter passing ahigh-frequency signal at 100 MHz or higher.

FIG. 4 is a block diagram showing an electric circuit of the monitorunit 20. In the drawing, 20 is the monitor unit, which is configured ofa reception antenna 21, a reception unit 22, a central processing unit23, a keyboard 24, a display unit 25, a transmission unit 26, atransmission antenna 27, and a power supply unit 28 supplying power tothem.

Here, the monitor unit 20 in the embodiment is a unit monitoringinformation such as air pressure information, which is transmitted fromthe internal-pressure detection unit 10, by receiving theelectromagnetic wave having the second frequency (300 MHz) that isradiated from the internal-pressure detection unit 10 while radiatingthe electromagnetic wave having the first frequency (100-300 KHz) to theinternal-pressure detection unit 10 as described later.

In addition, the reception unit 22 in the monitor unit 2 is configuredof a receiver 221 and an analog/digital (hereinafter, this is calledA/D) converter 222. The input side of the receiver 221 is connected tothe reception antenna 21, receives a 300-MHz high-frequency wave,detects this, and thereafter outputs the detected output to the centralprocessing unit 23 through the A/D converter 222.

The central processing unit 23 is configured of a known CPU 231 andmemory 232 that operate with a preset program, and, on the basis of aninstruction inputted from the keyboard 24, the CPU 231 not only storesinformation, inputted from the reception unit 22, in the memory 232, butalso displays the information on the display unit 25.

In addition, a transmission unit 26 is configured of a transmitter 261,and the transmitter 261 outputs a high-frequency signal at, for example,100-300 KHz to the transmission antenna 27 on the basis of a controlsignal from the CPU 231.

According to this embodiment having the configuration described above,the transmission unit 26 is driven at predetermined intervals on thebasis of an operating program in the CPU 231 from the monitor unit 20,the high-frequency signal of the first frequency or the high-frequencysignal at 100-300 KHz is radiated from the transmission antenna 27.

This electromagnetic wave is inputted to the transmission and receptionantenna 11 of the internal-pressure detection unit 10, and induceshigh-frequency current in the transmission and reception antenna 11. Thehigh-frequency current induced in the transmission and reception antenna11 is inputted to the rectifier circuit 12 through the low-pass filter16 a.

The high-frequency current inputted to the rectifier circuit 12 isrectified and supplied to the central processing unit 13, pneumaticsensor 14, and transmission unit 15 inside the internal-pressuredetection unit 10 as a power source.

Thereby, the central processing unit 13, to which the electric power issupplied while the electromagnetic wave transmitted from the monitorunit 20 is received, performs information transmission processingprogrammed beforehand. That is, the central processing unit 13 outputsthe air pressure information, based on a signal outputted from insidethe pneumatic sensor 14, to the transmission unit 15.

The transmission unit 15 modulates a carrier wave on the basis of theinformation inputted from the central processing unit 13, and suppliesthe modulated carrier wave or a high-frequency signal to thetransmission and reception antenna 11. Thereby, an electromagetic waveof the second frequency or an electromagnetic wave having the frequencyof 300 MHz is radiated from the transmission and reception antenna 11.

The monitor unit 20 receives the electromagnetic wave at 300 MHz, whichis radiated from the internal-pressure detection unit 10, by thereception unit 22 through the reception antenna 21, and the receptionunit 22 converts the information, which is received, into digital databy the A/D converter 222, and transmits the digital data to the centralprocessing unit 23.

The central processing unit 23 displays the information, which is basedon the digital data and is inputted from the A/D converter 222, or theair pressure information, which is received from, the internal-pressuredetection unit 10, on the display unit 25.

Thereby, it is possible to easily grasp the information of internal airpressure of the fender 1 provided separately from the monitoring station4 while staying at the monitoring station 4 without performing anyperiodical patrol as conventional ways.

As described above, according to this embodiment, it is unnecessary toprovide a power supply in the internal-pressure detection unit 10, andhence the internal-pressure detection unlit 10 can be semipermanentlyused. Therefore, since it is unnecessary to periodically replace abattery as conventional ways, it is possible to greatly reduce the laborof maintenance. Furthermore, according to this embodiment, since thedetection result is transmitted to the monitor unit by theelectromagnetic wave having the second frequency, it is unnecessary toinstall cables between the fender 1 and monitoring station 4 asconventional ways, and hence it is possible to omit the labor ofinstalling the cables.

Next, a second embodiment of the present invention will be described.

FIG. 5 is a block diagram showing an electric circuit of aninternal-pressure detection unit 10 in the second embodiment. In thedrawing, the same components as those in the first embodiment are shownby the same symbols, and description thereof is omitted. In addition, adifference between the first and second embodiments is that a detectionunit 17 and a memory unit 18 are provided in the internal-pressuredetection unit 10.

That is, the detection unit 17 is configured of a diode 171 and an A/Dconverter 172, and the anode of the diode 171 is connected to thetransmission and reception antenna 11 through the low-pass filter 16 a;and the cathode is connected to the CPU 131 of the central processingunit 13 through the A/D converter 172.

The memory unit 18 is configured of nonvolatile semiconductor memorysuch as EEPROM connected to the CPU 131, and anidentification-information inherent in each fender 1 (eachinternal-pressure detection unit 10) is stored beforehand in this memoryunit 18.

According to this embodiment having the configuration described above,the transmission unit 26 is driven at predetermined intervals on thebasis of an operating program in the CPU 231 from the monitor unit 20,and the high-frequency signal of the first frequency or thehigh-frequency signal at 100-300 KHz is radiated from the transmissionantenna 27.

This electromagnetic wave is inputted to the transmission and receptionantenna 11 of the internal-pressure detection unit 10, and induceshigh-frequency current in the transmission and reception antenna 11. Thehigh-frequency current induced in the transmission and reception antenna11 passes through the low-pass filter 16 a, and is then rectified by therectifier circuit 12 to be supplied to the central processing unit 13,pneumatic sensor 14, and transmission unit 15 inside theinternal-pressure detection unit 10 as a power source.

Thereby, the central processing unit 13, to which the electric power issupplied while the electromagnetic wave at 100-300 KHz is received,which is transmitted from the monitor unit 20, performs informationtransmission processing programmed beforehand.

That is, the central processing unit 13 outputs the air pressureinformation, based on a signal outputted from inside the pneumaticsensor 14, and the own identification-information, stored in the memoryunit 18, to the transmission unit 15. The transmission unit 15 modulatesa carrier wave on the basis of the information inputted from the centralprocessing unit 13, and supplies the modulated carrier wave or ahigh-frequency signal to the transmission and reception antenna 11.

Thereby, an electromagnetic wave of the second frequency or, anelectromagnetic wave having the frequency of 300 MHz is radiated fromthe transmission and reception antenna 11.

On the other hand, the monitor unit 20 receives the electromagnetic waveat 300 MHz, which is radiated from the internal-pressure detection unit10, with the reception unit 22 through the reception antenna 21; and thereception unit 22 converts the received information into digital data bythe A/D converter 222, and transmits the digital data to the centralprocessing unit 23.

The central processing unit 23 displays the information, which is basedon the digital data and is inputted from the A/D converter 222 or theair pressure information and identification-information, which isreceived from the internal-pressure detection unit 10, on the displayunit 25 in a one-to-one correspondence between them.

Therefore, according to the second embodiment, inherentidentification-information is assigned to each internal-pressuredetection unit 10, and hence, for example, if a plurality of fenders 1are managed, it is possible to securely identify each air pressure ofeach fender 1.

Next, a third embodiment of the present invention will be described.

FIG. 6 is a block diagram showing an electric circuit of a monitor unit20 in the third embodiment. In the drawing, the same components as thosein the second embodiment are shown by the same symbols, land descriptionthereof is omitted. In addition, difference between the second and thirdembodiments is that a modulation unit 29 is provided in the monitor unit20 and the transfer of air pressure information can be performed bydesignating an internal-pressure detection unit 10.

That is, the modulation unit 29 is configured of a DIA converter 291, amodulator 292, and a high-frequency amplifier 293, and the input side ofthe D/A converter 291 is connected to the CPU 231 in the centralprocessing unit 23; the output side is connected to the modulator 22.

The modulator 292 receives a carrier wave from the transmission unit 26,and modulates this with an output signal of the D/A converter 291 tosupply this to the high-frequency amplifier 293.

The high-frequency amplifier 293 amplifies the high-frequency signalinputted from the modulator 292 and outputs the signal to thetransmission antenna 27.

According to the internal-pressure detection apparatus having theconfiguration described above, not only identification-information ofeach internal-pressure detection unit 10 is transmitted at predeterminedintervals on the basis of an operating program in the CPU 231 from themonitor unit 20 to the modulation unit 29, but also the transmissionunit 26 is driven. Hence, the identification-information of eachinternal-pressure detection unit 10 is sequentially transmitted by thehigh-frequency signal of the first frequency or the high-frequencysignal at 100-300 KHz from the transmission antenna 27.

This electromagnetic wave is inputted to the transmission and receptionantenna 11 of the internal-pressure detection unit 10, and induceshigh-frequency current in the transmission and reception antenna 11.

The high-frequency current induced in the transmission and receptionantenna 11 of the internal-pressure detection unit 10 passes through thelow-pass filter 16 a, and thereafter is rectified by the rectifiercircuit 12 to be supplied to the central processing unit 13, pneumaticsensor 14, and transmission unit 15 inside the internal-pressuredetection unit 10 as a power source.

Furthermore, in the internal-pressure detection unit 10, the centralprocessing unit 13, to which the electric power is supplied while theelectromagnetic wave at 100-300 KHz is received, which is transmittedfrom the monitor unit 20, decides the identification-information,inputted through the detection unit 17. If thisidentification-information matches with the ownidentification-information stored in the memory unit 18, the centralprocessing unit 13 performs processing programmed beforehand.

That is, if the received identification-information matches with the ownidentification-information, the central processing unit 13 outputs theair pressure information, based on a signal outputted from inside thepneumatic sensor 14, to the transmission unit 15 and also reads the ownidentification-information stored in the memory unit 18 to output thisidentification-information to the transmission unit 15.

The transmission unit 15 modulates a carrier wave on the basis of theair pressure information and identification-information, which isinputted from the central processing unit 13, and supplies the modulatedcarrier wave or a high-frequency signal to the transmission andreception antenna 11. Thereby, an electromagnetic wave having thefrequency of 300 MHz is radiated from the transmission and receptionantenna 11.

On the other hand, the monitor unit 20 receives the electromagnetic waveat 300 MHz, which is radiated from the internal-pressure detection unit10, by the reception unit 22 through the reception antenna 21.

The reception unit 22 converts the received information into digitaldata by the A/D converter 222, and transmits the digital data to thecentral processing unit 23.

The central processing unit 23 displays the information, which is basedon the digital data inputted from the A/D converter 222, or the airpressure information and identification-information, which is receivedfrom the internal-pressure detection unit 10, on the display unit 25 ina one-to-one correspondence between them.

Therefore, according to the third embodiment, it is possible to transferair pressure information by designating an individual internal-pressuredetection unit 10. Hence, for example, if a plurality of fenders 1 aremanaged, information transmitted from respective fenders 1 may not beoverlapped, and hence it is possible to securely identify and detect airpressure of each fender

Next, a fourth embodiment of the present invention will be described.

Electric circuits of an internal-pressure detection unit 10 and amonitor unit 20 in the fourth embodiment are the same as those in thethird embodiment. A difference between the third and fourth embodimentsis that it becomes possible to write new information into memory unit 18by designating an arbitrary internal-pressure detection unit 10.

That is, in case of obtaining air pressure information from an arbitraryinternal-pressure detection unit 10, an air-pressure informationtransmission instruction, to which identification-information is added,is transmitted from the monitor unit 20.

An internal-pressure detection unit 10 having theidentification-information corresponding to theidentification-information of this instruction transmits the airpressure information and own identification-information to the monitorunit 20 according to the air-pressure information transmissioninstruction received.

In addition, when new information such as maintenance records is writteninto the memory unit 18 of an arbitrary internal-pressure detection unit10, a monitoring person sets identification-information designating theinternal-pressure detection unit 10, an information-write instruction,and information that is an object to be written, from the keyboard 24 onthe monitor unit 20, and transmits these.

Thereby, a high-frequency signal based on the information-writeinstruction is supplied from the transmission unit 26 in the monitorunit 20 to the transmission antenna 27. An electromagnetic wave having afrequency of 100-300 KHz is radiated from the transmission antenna 27.This electromagnetic wave is inputted to the transmission and receptionantenna 11 of the internal-pressure detection unit 10.

Thereby, while the internal-pressure detection unit 10 having the ownidentification-information that is the same as theidentification-information designated by the monitor unit 20 receivesthe electromagnetic wave transmitted from the monitor unit 20, thecentral processing unit 13, to which electric power is supplied,performs processing, programmed beforehand, according to theinformation-write instruction inputted through the detection unit 17.

That is, when the information-write instruction is received, the centralprocessing unit 13 of the internal-pressure detection unit 10 stores theinformation, which is an object to be written and is received along withthe instruction, at a predetermined address of the memory unit 18.Thereby, the information stored in the internal-pressure detection unit10 is updated.

In addition, when the information stored in the memory unit 18 of anarbitrary internal-pressure detection unit 10 is read, a monitoringperson sets identification-information, designating theinternal-pressure detection unit 10, and an information-read instructionfrom the keyboard 24 in the monitor unit 20, and transmits these.

Thereby, a high-frequency signal based on the information-readinstruction is supplied from the transmission unit 26 in the monitorunit 20 to the transmission antenna 27. An electromagnetic wave having afrequency of 100-300 KHz is radiated from the transmission antenna 27.This electromagnetic wave is inputted to the transmission and receptionantenna 11 of the internal-pressure detection unit 10.

Thereby, while the internal-pressure detection unit 10 having the ownidentification-information that is the same as theidentification-information designated by the monitor unit 20 receivesthe electromagnetic wave transmitted from the monitor unit 20, thecentral processing unit 13, to which electric power is supplied,performs processing, programmed beforehand, according to theinformation-read instruction inputted through the detection unit 17.

That is, when the information-read instruction is received, the centralprocessing unit 13 of the internal-pressure detection unit 10 reads theinformation, stored in the memory unit 18, and outputs this informationwith the own identification-information to the transmission unit 15.

The transmission unit 15 modulates a carrier wave on the basis of theinformation, which is read by the central processing unit 13, andsupplies the modulated carrier wave or a high-frequency signal to thetransmission and reception antenna 11. Thereby an electromagnetic wavehaving the frequency of 300 MHz is radiated from the transmission andreception antenna 11.

The monitor unit 20 receives the electromagnetic wave at 300 MHz, whichis radiated from the internal-pressure detection unit 10, by thereception unit 22 through the reception antenna 21. The reception unit22 converts the received information into digital data by the A/Dconverter 222, and transmits the digital data to the central processingunit 23.

The central processing unit 23 displays the information, which is basedon the digital data inputted from the A/D converter 222, or the storedinformation and identification-information, which are received from theinternal-pressure detection unit 10, on the display unit 25 in aone-to-one correspondence between them.

As described above, according to the fourth embodiment, it is possibleto easily update or rewrite the information stored in theinternal-pressure detection unit 10, and hence this may be effectivelyused if it is desired to hold and store maintenance history records orthe like of a fender 1 in the fender 1 itself.

In addition, the configurations in the first though fourth embodimentsare just exemplified, and hence the configurations of the presentinvention are not restricted by these.

Industrial Applicability

Electric energy for driving is supplied from a monitor unit to aninternal-pressure detection unit, provided in a pneumatic fender, by anelectromagnetic wave having a first frequency, and a detection result istransmitted from the internal-pressure detection unit to the monitorunit by an electromagnetic wave having a second frequency. Thereby, theinternal-pressure detection unit is driven by the energy of theelectromagnetic wave having the first frequency, and hence it isunnecessary to periodically replace a battery. Therefore, it is possibleto greatly reduce the labor of maintenance. At the same, time, since itis unnecessary to install cables between the pneumatic fender and amonitoring station provided with the monitor unit, it is possible toomit the labor of installing the cables. In addition, if a plurality ofpneumatic fenders, which are objects to be managed, exists, it ispossible to securely identify each internal air pressure to each fenderby assigning identification-information inherent in an internal-pressuredetection unit of each fender. Furthermore, it is possible to obtain adetection result of air pressure by designating a specificinternal-pressure detection unit by identification-information.Moreover, by providing means of information memory in aninternal-pressure detection unit and allowing the fender itself to storeand hold information such as maintenance history records of the fender,it is possible to easily access this information as the need arises.

FIG. 1

1 pneumatic fender

2 Quay

3 Bridge Pier

4 Monitoring Station

10 Internal-pressure detection unit

20 monitor unit

FIG. 2

1 Pneumatic fender

1 a Filler hole

10 Internal-pressure detection unit

FIG. 3

10 Internal-pressure detection unit

11 Transmission and reception antenna

12 Rectifier circuit

13 Central processing unit

14 Pneumatic sensor

15 Transmission unit

16 Duplexer

132 D/A converter

151 Oscillator

152 Modulator

153 High-frequency amplifier

FIG. 4

20 Monitor unit

22 Reception unit

23 Central processing unit

24 Keyboard

25 Display unit

26 Transmission unit

28 Power supply unit

221 Receiver

222 A/D converter

323 Memory

261 Transmitter

FIG. 5

10 Internal-pressure detection unit

11 Transmission and reception antenna

12 Rectifier circuit

13 Central processing unit

14 Pneumatic sensor

15 Transmission unit

16 Duplexer

17 Detection unit

18 Memory unit

132 D/A converter

151 Oscillator

152 Modulator

153 High-frequency amplifier

173 A/D converter

FIG. 6

20 Monitor unit

22 Reception unit

24 Keyboard

221 Receiver

222 A/D converter

28 Power supply unit

232 Memory

23 Central processing unit

25 Display unit

26 Transmission unit

261 Transmitter

292 D/A converter

293 Modulator

29 High-frequency amplifier

Modulation unit

What is claimed is:
 1. An internal-pressure detection apparatus for apneumatic fender that is fixed to an underwater structure or floated andis used as cushioning material for a ship or the like, comprising: aninternal-pressure detection unit provided in the pneumatic fender; and amonitor unit installed in a predetermined internal-pressure monitoringstation, wherein the internal-pressure detection unit comprises: apneumatic sensor that detects air pressure inside the pneumatic fenderand outputs an electric signal corresponding to a value of the airpressure; means of reception for receiving an electromagnetic wavehaving a first frequency; means of energy conversion for convertingenergy of the electromagnetic wave, received by the means of reception,into electric energy; and means of transmission for operating by theconverted electric energy, inputting an electric signal outputted fromthe pneumatic sensor, and transmitting a detection result of theinternal air pressure by an electromagnetic wave having a secondfrequency; means of identification-information memory for storingidentification-information inherent in each internal-pressure detectionunit; means of identification-information extraction for extracting theidentification-information included in a high-frequency signal receivedby the means of reception; means of identification-information matchingdecision for deciding matching the identification-information, extractedby the means of identification-information extraction, to theidentification-information stored in the means ofidentification-information memory; means of transmission drive controlfor driving the means of transmission when matching according to thedecision result; means of instruction extraction for extracting aninformation-read instruction and an information-write instruction whichare included in a high-frequency signal received by the means ofreception; means of information memory; for storing information aboutthe pneumatic fender means of information write for writing informationincluding updated information and additional information, which is anobject to be written and follows the information-write instruction intothe means of information memory when matching according to a decisionresult of means of the identification-information matching decision andreceiving the information-write instruction; the means of informationread for reading information, which is stored in the means ofinformation memory, when matching according to a decision result ofmeans of the identification-information matching decision and receivingthe information-read instruction; and the means of transmission fortransmitting the detection result of internal air pressure by thepneumatic sensor further comprising means for transmittingidentification-information stored in the means ofidentification-information memory, and information which is read by themeans of information read by the electromagnetic wave having the secondfrequency; and wherein the monitor unit comprises: means of transmissionfor transmitting the electromagnetic wave having the first frequency;means of reception for receiving the electromagnetic wave having thesecond frequency and converting the electromagnetic wave into anelectric signal; means of detection result extraction for extracting adetection result of the internal air pressure, which is included in theelectric signal outputted from the means of reception; and means ofinformation for informing of the detection result extracted by themeans, of detection result extraction; the means of memory for storingidentification-information of the internal-pressure detection unitprovided in the pneumatic fender that is an object to be detected; meansof instruction input for inputting an information-write instruction andinformation, which is an object to be written, to means of informationmemory in the internal-pressure detection unit, and an information-readinstruction from the means of information memory; means of transmissionincluding means for transmitting, identification-information of theinternal-pressure detection unit that is stored in the means of memory,and the instructions, which are inputted by the means of instructioninput, and information that is an object to be written by theelectromagnetic wave having the first frequency; means of informationextraction for extracting information that is stored in theinternal-pressure detection unit and is included in an electric signaloutputted from the means of reception; the means of detection resultextraction for extracting the detection result of internal air pressureincluding means for extracting identification-information from anelectric signal outputted from the means of reception; and the means ofinformation for informing of a detection result, which is extracted bythe means of detection result extraction including means for informinginformation, which is extracted by the means of information extraction,which are corresponding to identification-information extracted by themeans of detection result extraction.
 2. The internal-pressure detectionapparatus for a pneumatic fender according to claim 1, wherein the meansof information informs the identification-information and detectionresults that are extracted by the means of detection result extractionin a one-to-one correspondence between them.
 3. The internal-pressuredetection apparatus for a pneumatic fender according to claim 1, whereinthe means of information memory contains maintenance history records ofthe pneumatic fender.